Hello all,
I am using the uac2 kernel driver(drivers/usb/gadget/f_uac2.c) having kernel version 3.10.31 for an embedded board.
The board is presented as a USB device to a Linux PC having USB host controller in it.
I have added an interrupt endpoint in the uac2 kernel driver to support the status interrupt endpoint request as per usb audio 2.0 specification.
For the interrupt transfer to happen, I prepared the interrupt packet structure as per audio 2.0 specification and queued the endpoint to transfer it to the host driver. The interrupt structure is prepared as follows: bInfo : 0 (Interface request) bAttribute : 0x1 (CUR request) wValue : 0x200 (VOLUME feature unit control selector) wIndex : 0x700 (FEATURE UNIT ID)
As per my understanding, when the above interrupt endpoint is transferred to host in response to Interrupt IN request, the host should send me a GET CUR volume class-specific request to further qualify the cause of interrupt.
However, I am not getting any class-specific request from host in response to the status interrupt transferred to host.
My query is do i need to implement a mixer interface in the uac2 kernel driver to get the request or i am doing something wrong in the process.
I am stuck onto this and cannot proceed further.
Thanks Puneet